ap2s2k

iTrader: (3)

Hey everyone, I had an interesting (weird) observation when I was installing my new borla cat back exhaust last week. When I jacked up the car I took off oem exhaust and was fitting borla, all of the sudden I heard like a pressure pump in the fuel tank started to build pressure, I was under the car and thought to myself if I hit a wire or something while fitting pipes around, car was off for few hours btw. So I got up and opened the fuel tank cap, the pressure was released and the (electric) noise stopped. Didn't hear that before and I always park in a garage so I should of notice something like that before.

Joe Z

iTrader: (10)

Digger08 is posting the technical answer for this...

It's EVAP canister related & very normal

~ Joe Z

digger08

iTrader: (1)

You must be psychic!........I'm pretty sure when you bought the car new there was a warning card in the armrest or glove box that speaks to this....high pressure fuel pump may make noises and not to be concerned, after shutting the car off.


Picture here...you decide if its related or not




Digger08

ap2s2k

iTrader: (3)

awesome guys, thanks a lot, I didn't buy my car new so I've never see this notice card before

todd4566

Good knowledge. I was also unaware of this feature (second owner).

lobuxracer

iTrader: (2)

It's not the HPFP, it's a separate pump installed to test the integrity of the evaporative emissions control. EVAP is the hardest emissions requirement to meet, and all the OEMs have had to install pumps to check for leaks in the EVAP system (see pump module in diagram below). As the message states, it usually does this test 5 hours after the vehicle has been shut off. All current vehicles are doing this to comply with EPA requirements. It's the only way it can be done.

I8ABMR

My LS and GS did the same thing. Kind of trips you out